The invention is related to providing a refrigerator, and in particular, to providing a refrigerator having high efficiency multi-evaporator cycle(H.M. CYCLE) and control method thereof for performing the refrigerating and freezing of the constant temperature in each of divided compartment thereof by using separate evaporators and their related fans.
In general, a refrigerator comprises a body 4 into which a freezing compartment 2 and a refrigerating compartment 3 are divided from each other by a middle partition 1 with doors 5 and 6 being provided as shown in FIG. 1. The refrigerator has a refrigerating cycle including a compressor 7, a condenser 8, a capillary tube 9 and an evaporator 10 connected in turn by means of refrigerant tubes 11 to one another forming a closed loop as shown in FIG. 2. In other words, The refrigerant performs the refrigerating cycle operation for the purpose of the energy state conversion during passing through the refrigerant tubes 11 and various components. Especially, the evaporator 10 absorbs the heat from around its circumference and generates cooled air.
Referring to FIG. 1, the compressor 7 is mounted on the lower portion of the body 4, and the evaporator 10 is mounted in the rear wall of the refrigerating compartment 2. A cooling fan 12 is provided over the upper portion of the evaporator 10. A fan guide 14 and a cooled air duct 15 each having cooled air discharging portions 13 are provided at proper places in the rear wall of the refrigerator body 4, so that a part of cooled air heat-exchanged at the evaporator 10 is supplied through the discharging portion 13 of the fan guide 14 into the freezing compartment 2, and the remainder is introduced through the discharging portion 13 of the cooled air duct 15 into the refrigerating compartment 3. And then after the cooled air is circulated in each compartment, it again returns to the evaporator 10 to be heat-exchanged through first and second feed-back passages 17 and 18 which are formed on a middle partition 1. An adjusting damper 18 is for adjusting an amount of cooled air to be supplied to the refrigerating compartment 3.
Referring to FIG. 3, the refrigerator is ordinarily controlled according to the method of the prior art as follows: the temperature T.sub.F of the freezing compartment 3(called "freezing temperature" below) is detected in order to determine whether the compressor 7 is operated or not. The freezing temperature T.sub.F is compared with the freezing set temperature T.sub.FS previously set by using a temperature adjuster. Therefore, control performs at step 110 to determine whether the freezing temperature T.sub.F is larger than the freezing set temperature T.sub.FS of the freezing compartment(called "the freezing set temperature" below). If the temperature T.sub.F is over the freezing set temperature T.sub.FS, step 110 goes onto step 111 to turn on the compressor 7 and the cooled fan 10. If the freezing temperature T.sub.F is below the freezing set one T.sub.FS, step 110 goes onto step 112 to turn off the compressor 7 and the cooling fan 10. After the respective operation of steps 111 and 112, control executes step 113 to determine whether the temperature T.sub.R of the refrigerating compartment 3(called "refrigerating temperature" below) is larger than the set temperature T.sub.RS of the refrigerating compartment(called "the refrigerating set temperature below) previously set by using a temperature adjuster according to their comparison results. If the refrigerating temperature T.sub.R is over the refrigerating set one T.sub.RS, step 113 goes onto step 114 to open the adjusting damper 18. On the contrary, if the refrigerating temperature T.sub.R is below the refrigerating set one T.sub.RS, step 110 goes onto step 115 to close up the adjusting damper 18.
Therefore, during the operation of the compressor 7 and the cooling fan 10, the adjusting damper 18 is operated to supply a proper amount of cooled air into the refrigerating compartment 3, but when the compressor 7 is turned off, even through the adjusting damper 18 is opened based on the fact that the refrigerating temperature T.sub.R is higher than the refrigerating set temperature T.sub.RS, under the non-operation of the cooling fan 10 the introduction of the cooled air into the refrigerating compartment 3 does not smoothly happen. It means the temperature rise in the refrigerating compartment 3. Furthermore, the amount of of the cooled air into the refrigerating compartment 3 does not smoothly happen. It means the temperature rise in the refrigerating compartment 3. Furthermore, the amount of cooled air can be adjusted, but the temperature of the refrigerating compartment represents the greater deviation according to the operation or non-operation of the compressor 7. As a result, the constant temperature refrigerating is very difficult.
The freezing compartment and the refrigerating compartment are set to be respectively kept at 3.degree. C. and -18.degree. C. under the standard temperature condition. Then, it has problems in that there are no any limitation in controlling two temperature ranges using one heat-source or cooler and the energy efficiency reduction of the refrigerator. In other words, in case that one heat-exchanger controls two temperature ranges of the refrigerating and freezing compartments by the predetermined temperatures, the heat-exchanger, the refrigerating compartment and the freezing compartment each may show greater differences between their temperatures caused during operating and non-operating. It means the generation of the non-reversible loss in a thermodynamic respect, following by the reduction of the energy efficiency.
The refrigerator is configured so that the freezing and refrigerating compartments are communicated to each other through the ducts and the feed-back passages. It has problems in that the moisture emitted from foodstuffs of the refrigerating compartment makes much frost on the surfaces of the heat-exchanger having lower temperature, an amount of wind passing through the heat-exchanger is reduced, and thus the energy efficiency of the refrigerator is decreased.
The refrigerator has complex procedures of generating cooled air at the heat-exchanger, guiding it through the cooling duct, adjusting an amount of cooled air and supplying the adjusted amount of cooled air to the refrigerating compartment. It takes much time to make the refrigerating compartment maintained at the predetermined temperature 3.degree. C. Especially, at the time of the initial starting up or re-starting of the refrigerator after the long-time's stopping, it takes much time under the high temperature condition of about 30.degree. C. to maintain the refrigerating compartment at the standard temperature. It is not also possible to quickly respond to the temperature changes of the refrigerating compartment. That is why the constant temperature refrigerating is not realized. To it, the refrigerator is proposed to provide an exclusive fan in each of the freezing and refrigerating compartments, but only one heat-exchanger is mounted in the freezing compartment. It has not only a limitation in cooling the refrigerating compartment in a high speed but also a problem in that the respective control of the refrigerating and freezing compartments can not be performed.
The refrigerator also has a problem in that a large amount of frost is formed on the heat-exchanger, because the cooled air becomes wet air during returning to the heat-exchanger through the feed-back passage after the circulation in the refrigerating compartment. The frost does not melt away during the non-operation of the refrigerator, so that it causes the refrigerating compartment to be dried. Whereby, the stored foodstuffs can not be kept fresh in the refrigerating compartment for a long time period.
The refrigerator has a bad effect on the foodstuffs and ices stored in the freezing compartment due to the odors, etc. of foods such as a kimchi called fermentation vegetables, because the cooled air separately supplied to the refrigerating and freezing compartments are fed back to the heat-exchanger, mixed with each other and then supplied thereto.
The refrigerator requires the cooled air duct for distributing cooled air generated at the heat-exchanger to the refrigerating and freezing compartments, respectively, and a feed-back passages for guiding cooled air to be fed-back to the heat-exchanger. Thus, it causes the complex of the configuration and the loss of cooled air related thereto.
A typical prior art is U.S. Pat. No. 5,150,583 that discloses a refrigerator including a refreezing compartment provided with an evaporator and a fan and a refrigerating compartment provided with an evaporator and a fan. The refrigerator is to presuppose the use of the non-azeotrope mixture refrigerant having two components of boiling points different from each other. In case of using the non-point of a high temperature range is used for cooling the refrigerating compartment, and the refrigerant having the melting point of a low temperature range is used for cooling the freezing compartment. Therefore, it has an advantage in that two refrigerant enables the heat-exchanger to have the smaller heat transferring temperature difference to air in compartments over their own temperatures and decrease the thermal dynamic non-revisable loss, thereby improving the energy efficiency. But, it requires the wider heat transferring area of the heat-exchanger in order to accomplish the predetermined heat-transferring, which means that the heat-exchanger becomes larger. Also, a gas-liquid separator must be provided in the pipe laying, because it is not necessary to introduce refrigerant evaporated in the high temperature area into the low temperature one. The adjustment of the appropriate mixing ratio of two refrigerants is difficult. Even if the mixing of two refrigerants is exactly accomplished, the mixed state has the potential possibility to be changeable in each component of the refrigerating cycle. The mixing ratio also is changeable according to the load state of compartments or the open air temperature out of the refrigerator. Furthermore, during the mass-producing of products it is more difficult to seal two refrigerants into the pipe laying at the exact mixing ration. If a predetermined allowable error is existed in the sealed amount of refrigerant, the mixture refrigerant deteriorates its own inherent performance.
The main object of the invention is to provide a refrigerator having high efficiency multi-evaporator cycle(H.M. CYCLE: called "H.M. cycle" below) and control method thereof for performing the refrigerating and freezing of the constant temperature and the high humidity in each of independently divided compartment thereof by using separate evaporators and their related fans.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof for controlling the operating of a system in a different manner according to the state of open air out of the refrigerator, thereby cooling the freezing and refrigerating compartments, quickly and efficiently.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof, comprising independent divided freezing and refrigerating compartments, each of which is provided with an evaporator and an air circulation fan(called "fan" below) to respectively be controlled, so that the temperature difference between the compartment and its evaporator is reduced, thereby decreasing the thermal dynamic non-reversible loss according to the system control and enhancing the energy efficiency.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof for performing the defrosting of the evaporator, using the refrigerating air of a relatively higher temperature during the turning-off of a compressor and then circulating the melted moisture to form the high humidity environment in the refrigerating compartment, thereby enabling the fresh food storage for a long time period.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof, comprising independent divided freezing and refrigerating compartments provided with a cooling system(an evaporator and an air circulation fan) to control each compartment, independently, thereby improving the cooling speed of each compartment.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof, comprising independent divided freezing and refrigerating compartments provided with a cooling system(an evaporator and an air circulation fan) to control each compartment, independently, thereby improving the air circulating speed, as well as to detect the temperature, minutely, by means of a sensor installed in each compartment, thereby responding to the temperature rising, quickly.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof, comprising completely separated freezing and refrigerating compartments to prevent odors emitted from stored foodstuffs such as pickled vegetables from being circulated into each other.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof, comprising a cooling system provided with two evaporators and two fans, thereby simplifying the configuration of the refrigerating cycle and enables single refrigerant to be used, thereby improving the mass-production.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof for operating the freezing and refrigerating fans, simultaneously, thereby improving the cooling speed.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof for operating the freezing and refrigerating fans, in a manner that if the temperature of the freezing evaporator is the freezing one, the operation of the freezing fan is delayed until the temperature of the refrigerating evaporator becomes below the refrigerating one, thereby saving the energy.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof for turning on a compressor according to the state of the freezing or refrigerating compartment and for controlling the freezing and refrigerating fans, independently, thereby maintaining each compartment at the set temperature.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof for first cooling the refrigerating compartment and then cooling the freezing compartment after the temperature of the refrigerating compartment becomes below the refrigerating set one, thereby decreasing the operating time of the compressor and saving the energy.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof for enabling the refrigerating compartment to be maintained at the constant temperature even during the cooling of the freezing compartment.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof for cooling the refrigerating compartment at the initial operation, so that the freeing compartment is cooled before the refrigerating compartment is cooled below the refrigerating temperature, thereby improving the cooling speed of both compartments.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof for preventing the temperature of the freezing compartment from being exceeded over the freezing set one even during the cooling of the refrigerating compartment, thereby performing the cooling of the refrigerating compartment at the constant temperature.
Another object of the invention is to provide a refrigerator having H.M. cycle and control method thereof for enabling the freezing compartment to be maintained at the constant temperature even during the cooling of the refrigerating compartment as well as for enabling the refrigerating compartment to be maintained at the constant temperature even during the cooling of the freezing compartment.